In standing mixer fitted with a paddle attachment, mix the margarine and sugars until light and fluffy, about 5 minutes, scraping the sides and scooping the bottom once or twice to incorporate the margarine.
Add the applesauce, vanilla paste and lemon zest and mix to fully incorporate.
Sift the flour, baking powder, cinnamon, and salt onto a sheet of parchment paper or into a medium bowl.
Add the flour to the margarine and mix until completely incorporated.
Scrape the batter onto a sheet of plastic wrap. Pat flat, about 1-inch thick, and cover completely with plastic wrap. Refrigerate overnight.
Remove the dough from refrigerator 15 to 20 minutes before proceeding.
Preheat oven to 375°F. Line a sheet pan with silpat liners or parchment paper.
Place a second sheet of parchment paper, the same length as sheet pan, on work surface. Roll the dough into a rectangle about 14 inches long (or 2 inches shorter than your baking sheet) by 6 inches wide. Evenly spread the filling from end to end along one side of the dough’s long edge, about 2 inches wide. Lift the parchment paper and roll the dough lengthwise in a log, 2 to 2½ inches wide. Flip onto the prepared baking sheet and flatten evenly with your hand into a rectangle.
Brush with rice or hemp milk and sprinkle with demarara sugar. Bake until the dough has turned a pale, nutty brown and the filling is heated through, about 12 to 15 minutes.
When done, remove and allow to cool in the pan. Cut into 2 to 2½-inch squares.